• Title/Summary/Keyword: S-doping

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Electron Paramagnetic Resonance of the I2-Doped PBMPV Conducting Polymers

  • Lee, C. H.;Lee, Cheol-Eui;J.-I. Jin;S.-J. Chung
    • Journal of Magnetics
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    • v.2 no.4
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    • pp.123-125
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    • 1997
  • We have studied a series of I2-doped poly [2-buthoxy-5-methoxy-1, 4-phenylenevinylene] (PBMPV) conducting polymers by means of electron paramagnetic resonance (EPR) measurements. In this work, the EPR linewidth and spin density were obtained from the EPR intensity and studied as a function of the degree of doping.

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The Concentrations and TEQ Levels of PCDFs and PCDDs in Human Adipose Tissue and First Breast Milk of Korean (체지방 조직 및 초유중에 잔류되어 있는 다이옥신 함유도에 관한 연구)

  • Kim, Yunje;Lee, Sun Young;Han, Soon Young;Park, Kui Lea;Kil, Kwang Sup;Yang, Kyu Hwan;Kim, Eun Kyung;Kim, Myungsoo
    • Analytical Science and Technology
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    • v.14 no.6
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    • pp.504-509
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    • 2001
  • The concentrations and TEQ levels of PCDFs/PCDDs in human aipose tissue and first breast milk were analyzed by high resolution gas chromatography/high resolution mass spectrometry. The human adipose tissue samples measured in this study have been collected at hospital in Seoul. The total concentration and TEQ level of PCDFs were showed 5.812 pg/g and 1.485 pgTEQ/g. The total concentration and TEQ level of PCDDs were showed 26.648 pg/g and 1.176 pgTEQ/g, respectively. This paper also reported dioxin levels in 20 breast milks of Korean mothers from hospital in Seoul National University. Total concentration and TEQ levels of PCDFs were showed 7.019 pg/mL and 0.177 pgTEQ/mL, respectively. Total concentrations and TEQ levels of PCDDs were showed 14.224 pg/mL and 0.693 pgTEQ/mL, respectively. According to the contribution of dioxin congeners in samples, PCDDs was higher than PCDFs. And OCDD had the highest concentration.

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Lithium Transition Metal Phosphate Cathodes for Advanced Lithium Batteries (리튬이온전지에서 새로운 양극재료를 위한 금속인산화물)

  • ;Yet Ming Chiang
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.26-26
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    • 2003
  • Lithium storage electrodes for rechargeable batteries require mixed electronic-ionic conduction at the particle scale in order to deliver desired energy density and power density characteristics at the device level. Recently, lithium transition metal phosphates of olivine and Nasicon structure type have become of great interest as storage cathodes for rechargeable lithium batteries due to their high energy density, low raw materials cost, environmental friendliness, and safety. However, the transport properties of this family of compounds, and especially the electronic conductivity, have not generally been adequate for practical applications. Recent work in the model olivine LiFePO$_4$, showed that control of cation stoichiometry and aliovalent doping results in electronic conductivity exceeding 10$^{-2}$ S/cm, in contrast to ~10$^{-9}$ S/cm for high purity undoped LiFePO$_4$. The increase in conductivity combined with particle size refinement upon doping allows current rates of >6 A/g to be utilized while retaining a majority of the ion storage capacity. These properties are of much practical interest for high power applications such as hybrid electric vehicles. The defect mechanism controlling electronic conductivity, and understanding of the microscopic mechanism of lithiation and delithiation obtained from combined electrochemical and microanalytical techniques, will be discussed

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Two-dimensional modelling of uniformly doped silicene with aluminium and its electronic properties

  • Chuan, M.W.;Wong, K.L.;Hamzah, A.;Rusli, S.;Alias, N.E.;Lim, C.S.;Tan, M.L.P.
    • Advances in nano research
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    • v.9 no.2
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    • pp.105-112
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    • 2020
  • Silicene is a two-dimensional (2D) derivative of silicon (Si) arranged in honeycomb lattice. It is predicted to be compatible with the present fabrication technology. However, its gapless properties (neglecting the spin-orbiting effect) hinders its application as digital switching devices. Thus, a suitable band gap engineering technique is required. In the present work, the band structure and density of states of uniformly doped silicene are obtained using the nearest neighbour tight-binding (NNTB) model. The results show that uniform substitutional doping using aluminium (Al) has successfully induced band gap in silicene. The band structures of the presented model are in good agreement with published results in terms of the valence band and conduction band. The band gap values extracted from the presented models are 0.39 eV and 0.78 eV for uniformly doped silicene with Al at the doping concentration of 12.5% and 25% respectively. The results show that the engineered band gap values are within the range for electronic switching applications. The conclusions of this study envisage that the uniformly doped silicene with Al can be further explored and applied in the future nanoelectronic devices.